1. INTRODUCTION Coal mill is an important component of the thermal power plant. It is used to grd and dry the moisturized raw coal and transport the pulverized coal air mixture to the boiler. Poor dynamic performance of coal mill will lead to decrease the overall efficiency of the power plant, slow load take up rate and frequent shut down.
Specifically, feness is a measurement of the percentage of a coal sample that passes through a set of test sieves usually designated at 50, 100, and 200 mesh A 70% coal sample passg through a 200 mesh screen dicates optimum mill performance. The mill wear and the power consumption are creased if the 70% value is exceeded. Values lower than 70% mean higher carbon loss and creased fuel consumption. In addition, coal retaed on the 50 mesh screen should be the 1–2% range.